A turbofan gas turbine engine basically includes a core portion which must be mounted inside a bypass duct. A traditional engine mount system for a fuselage mount turbofan gas turbine engine reacts to thrust, lateral and vertical loads at the front mounting plane (on the intermediate case of the engine), and reacts to lateral and vertical loads at the rear mount. The rear mount is usually located either on the bypass duct, forming a cantilever core as schematically shown in FIG. 9, or on the engine core, typically near the turbine exhaust case, forming a rear core mount as schematically shown in FIG. 10. However, the cantilever core suffers from distortion due to inertia loads and tends to droop from the burden of these loads, resulting in tip clearance loss which is critical to the functioning of an axial compressor. The rear core mount suffers from significant bending of the core portion caused by thrust loads. The rear mount carries a load due to a moment created by the engine thrust line of action being offset from the thrust reaction plane. Thus, the core portion is loaded analogous to a simply supported beam with a point moment located at the front mount plane. This effect is particularly evident on an axial compressor, since the maximum deflection occurs at the rear compressor stages, where small tip clearances are needed to maintain engine operability. Increased carcass bending results in having to set larger initial tip clearances, which results in both loss of efficiency in the compressor and turbine, and is therefore critical for the operability of an all-axial compressor.
Accordingly, there is a need to provide an improved mounting system for turbofan gas turbine engines.